That shouldn't be a problem. It seems like all the Bob Ross paintings are owned by a very small group. If you buy a Bob Ross painting and the provenance doesn't include any of those people you probably have a forgery.
No, the sources are horrible. You can easily fake up any number of Bob Rosses and simply say, "ah yes, I discovered another one of the tens of thousands of Bob Rosses which he sold as a young man or whipped out in a charity event in a small podunk place, and the original owners prefer anonymity". In terms of provenance, the sheer number, blandness, and indiscriminate original distribution of paintings makes it sound like a nightmare. If the market were more developed, so selling Rosses wasn't so unusual, I bet forgery would become a much bigger problem (although you wouldn't be able to tell if done somewhat competently - how hard would it be to get paintings and canvases from the '80s and defeat pretty much every possible forensics? that was not long ago at all... We're not talking trying to forge Renaissance masters here.)
I don't think that's true based on the article: they say that he sold 1000s of paintings in flea markets as well as before he became famous, those owners may not know they own a bob ross but the paintings exist and thus there's a plausible explanation for the forgery.
My mistake. I only skimmed the article since it was similar to a video I'd seen recently on the topic [0]. If they mentioned the flea markets in the video I forgot that detail.
"If you buy a Bob Ross painting and the provenance doesn't include any of those people you probably have a forgery."
But are the buyers of his paintings actually checking, and do those who are buying just to flip even care as long as they can quickly pawn it off to the bigger sucker?